Central venous catheters (CVCs) are used to provide medication to patients to treat conditions that might require longer courses of treatment, for example, pain, infection, or cancer, or to supply nutrition. A central venous catheter can be left in place longer than an intravenous catheter (IV), which delivers medications into a vein near the skin surface. Biofilms can occur in CVCs and they comprise an accumulation of bacteria, e.g. S. epidermidis, on and into the surface of the CVC. The biofilm can be difficult to treat because some bacteria may be in a stationary phase and/or the biofilm may be difficult to penetrate.